Is the fast of one who had a wet dream after Fajr in Ramadan and did not perform ghusl until after Maghrib accepted? And what must he do?

A wet dream during the daytime in Ramadan (definition) does not invalidate the fast, because it is something unavoidable, and "Allah does not burden a soul beyond its capacity." However, delaying the ritual bath (ghusl (definition) al-janabah (definition)) until Maghrib is not permissible, as it would lead to missing the Dhuhr and Asr prayers.